The actual work that needs to be accomplished to meet your project goals can be broken into tasks. For example, painting museum walls and hanging clocks are tasks that, when combined with other tasks, result in the completion of a clockwork exhibit. But putting on a clockwork exhibit is the goal of that set of tasks — it is not a task itself.
The scope of a project consists of all its tasks and all its goals. Cutting scope, for instance, often means eliminating some goals and the tasks needed to fulfill those goals.